The purpose of this study was to determine the behaviour of porous scaffolds produced from gel-derived powders of the CaO-SiO3-P2O5 system in vivo. Two starting powders with different chemical compositions, designated S2 (high silica amorphous material with a composition in mol% of 80SiO2, 16CaO, 4P2O5) and A2 (high lime glass-crystalline material with a composition in mol% of 40SiO2, 54CaO, 6P2O5). The gel-derived powders were sintered using pyrolysable additions and by slip casting on a polymeric sponge. The phase compositions, densities and open porosities of the sintered material were characterised. After sintering, the A2 material contained hydroxyapatite and wollastonite as crystalline phases, while S2 material contained crostobalite and small amounts of apatite as crystalline phases. An SBF in vitro test was carried out to estimate the bioactive properties of the materials obtained. It was found that HAp formation on the sinter surface occurs only int he case of A2 biomaterials with a high calcium concentration. For in vivo examination cylindrical porous samples 5mm in diameter by 5mm high of S2 and A2 materials were implanted into bone defects in rabbits. After 3 and 6 months implantation, the rabbits were killed and the implanted bone preparations were examined. Radiological observations showed that S2 samples were slightly better incorporated into the bone defects and osteolysis was not observed.
